\begin{table}[htbp]\centering
\def\sym#1{\ifmmode^{#1}\else\(^{#1}\)\fi}
\caption{Table: Firms in specific and generic sectors}
\begin{tabular}{l*{1}{ccc}}
                    &\multicolumn{3}{c}{Specific vs Generic}        \\
                    &    Specific&     Generic&Specific-Generic/t-stat         \\
Judicial efficiency &        2.36&        2.29&        0.06\sym{***}\\
                    &            &            &      (6.90)         \\
Value added per worker (Thousand dollars)&       65.77&       48.03&       17.74\sym{***}\\
                    &            &            &     (11.74)         \\
Capital stock per worker (Thousand dollars)&       55.39&       43.64&       11.75\sym{***}\\
                    &            &            &      (6.63)         \\
Proportion of skilled workers&        0.68&        0.70&       -0.02\sym{***}\\
                    &            &            &     (-6.91)         \\
Number employees    &      136.56&      132.70&        3.86         \\
                    &            &            &      (0.38)         \\
New firm            &        0.03&        0.04&       -0.01\sym{***}\\
                    &            &            &     (-6.95)         \\
\end{tabular}
\end{table}
